The Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs encourage small businesses to engage in Federal Research/Research and Development (R/R&D) with the potential for commercialization.
Participating Agencies post SBIR/STTR funding opportunities on a regular periodic basis throughout the year. Some agencies have multiple solicitations throughout the year, while others may only have one solicitation release each year (View Open Solicitations).
Solicitation guidelines can very quite a bit across different agencies, especially between agencies that provide awards as grants and those that use contracts.
In order to get specific guidelines, visit the agency SBIR program site to read the official version of the solicitation and download the appropriate forms and rules.